I. Classification of seed-bearing vascular plants, phyum Tracheophyta

 A. Gymnosperms - (gymnos = naked) seeds, evergreen, do not shedleaves

  1. Class Coniferae - woody trees and shrubs with needle-likeleaves (pines, redwood, yew)
  2. Class Cycads - biggest cones, found in tropics
  3. Class Gingkos - male trees are ornamentals, female treesstink
  4. Class Gnetophytes - desert shrub, Ephedra

 B. Class Angiosperms, fruits cover seeds

  1. Subclass Monocotyledoneae (80,000 - includes orchids, palms,grasses, cereal crops)

   a. one embryonic leaf
   b. vascular tissue is dispersed
   c. parallel veination
   d. flower parts occur in threes or multiples of threes

  2. Subclass Dicotyledoneae (180,000 spp)

   a. two embyronic leaves
   b. vascular tissue is in a circular bundle
   c. net veination in leaves
   d. flower parts occur in fours or fives or multiples

II. Reproduction - trend toward sporophyte dominance

 A. Gymnosperms

  1. Large diploid sporophyte - tree
  2. Reproductive structures are cones

   a. male cones produce haploid microspores

    1. pollen grains
    2. mitosis occurs inside, but only two cells survive- tube and generative cells
    3. when pollen germinates, it grows a pollen tube,and two sperm cells
    4. pollen tube grows until it reaches archegonia- may take 1 year

   b. female cones have 2 sporangia on scales, each givesrise to 4 haploid megaspores

    1. Only 1 megaspore survives, then grows by mitosisto produce gametophyte
    2. 2-5 archegonia produce egg cells
    3. Integument, female gametophyte, and egg cellsis an ovule or seed

  3. Zygote is formed after fertilization and remains inside seed. Seed has

    1. seed coat derived from integument
    2. stored food from female gametophyte
    3. embryo

 B. Angiosperms

  1. Large diploid sporophyte - plant
  2. Reproductive structures are flowers

   a. male flowers produce haploid microspores

    1. pollen grains occur in stamens - anthers and filaments
    2. mitosis occurs inside, but only two cells survive- tube and generative cells
    3. when pollen germinates, it grows a pollen tube,and two sperm cells
    4. pollen tube grows until it reaches egg cells

   b. female flowers have pistils with ovaries and styles. Ovules occur in carpels

    1. Meiosis occurs once in each ovule, producing 1surviving haploid megaspore
    2. Megaspore divides twice, with one cell getting2 nuclei (female gametophyte)

  3. Both haploid and diploid cells in ovule are fertilized forming

   a. diploid embryo
   b. triploid endosperm
   c. ovary typically develops into the fruit

  4. Angiosperms differ from Gymnosperms by

   a. flowers instead of cones
   b. ovules are inside sporophyll, not on the surface
   c. gametophytes are more reduced
   d. have fruits
   e. have double fertilization

III Structure

 A. Nutrient and water transport - vascular tissue

  1. Xylem - channelled cells which take water and nutrient fromroots to shoots
  2. Phloem - channelled cells which transport sugar throughoutplant

 B. Growth and support

  1. Meristems - mitotically active cells, apical and lateral
  2. Permanent tissue
  3. Woody plants used dead tissue as bark, called periderm
  4. fill cells with lignin to make wood
 

IV Key adaptations for life on land
 

	Bryophytes	Ferns	Gymnosperms	Angiosperms
Plumbing	nonvascular	vascular	vascular	vascular
Dominant form	haploid	diploid	diploid	diploid
Gametophyte	large independent	small independent	small, attached	v sm, attached
Spores	one type	one type	two types	two types
Gamete motility	motile sperm	motile sperm	nonmotile*, pollen	nonmotile, pollen
Seed	absent	absent	naked	covered with fruit
Repro structure	sporangium	sporangium	cone	flower
Pollination	-	-	wind	animal
Fertilization	single	single	single	double

*true for conifers

V. Evolutionary questions to consider

 A. Why do almost all multicellular organisms begin each generationfrom a single cell?

 B. Why have diploid phases supplanted haploid phases in most lineagesof organisms?

 C. Why does sexual recombination often occur when the environmentchanges for the worse?

 D. Why do angiosperms have a triploid endosperm?